Mars has always had an allure to us mere earthlings. When Orson Welles broadcast the War of the Worlds on October 30, 1938, that an invasion was coming from Mars, thousands of Great Depression-stricken Americans panicked. Sixty-six years later, America struck back (well, figuratively), with President George W. Bush announcing in January 2004 an ambitious plan for a manned mission to Mars. As Bush declared, “With the experience and knowledge gained on the moon, we will then be ready to take the next steps of space exploration: human missions to Mars and to worlds beyond.” While the Great Depression may have primed Americans to fear fictitious Martians, today’s Great Recession has made us fearful of spending the money to go there, so President Barack Obama announced earlier this year that America would cancel Bush’s plan but instead develop a new plan that would get us to Mars by around 2035.

Maybe it wasn’t a manned mission, but 35 years ago today, on August 20, 1975, the U.S. launched Viking 1, the first of two robotic U.S. spacecraft launched by NASA for an extended study of Mars. As Britannica’s article discusses:

Viking 1 and Viking 2, which lifted off on August 20 and September 9, 1975, respectively, each comprised an instrumented orbiter and lander. After completing nearly yearlong journeys, the two spacecraft entered orbits around Mars and spent about a month surveying landing sites. They then released their landers, which touched down on flat lowland sites in the northern hemisphere about 6,500 km (4,000 miles) apart. Viking 1 landed in Chryse Planitia (22.48° N, 47.97° W) on July 20, 1976; Viking 2 landed in Utopia Planitia (47.97° N, 225.74° W) seven weeks later, on September 3.

The Viking orbiters mapped and analyzed large expanses of the Martian surface, observed weather patterns, photographed the planet’s two tiny moons (Deimos and Phobos), and relayed signals from the two landers to Earth. The landers measured various properties of the atmosphere and soil of Mars and made color images of its yellow-brown rocky surface and dusty pinkish sky. Onboard experiments designed to detect evidence of living organisms in soil samples ultimately provided no convincing signs of life on the surface of the planet. Each orbiter and lander functioned long past its design lifetime of 90 days after touchdown. The final Viking data was transmitted from Mars (from the Viking 1 lander) in November 1982, and the overall mission ended the following year.